Astrophotography Hints & Tips
Film Info
Don Westergren's Film Tests
Robert Reeves Film Review
Kodak Wratten filters
Filter#
lambda (50%)
Transmission H-alpha
# 25
600 nm
88%
# 29
622 nm
89%
# 92
639 nm
76%
Good, covers all bands,
much cheaper than O-III,
better transmission.